Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism
Reexamination Certificate
1999-12-01
2002-11-19
Sniezek, Andrew L (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
C360S092100
Reexamination Certificate
active
06483655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic-tape library system for accurately mounting a magnetic tape on a magnetic-tape drive by using a hand assembly mounted on an accessor and a method for controlling the positioning of an accessor to the magnetic-tape drive.
2. Description of the Prior Art
A cartridge tape must be accurately transferred from a cartridge-tape storing rack (or cell in a drum unit) to a magnetic-tape drive. By improving the mechanical accuracy of each component unit of a magnetic-tape library system, the possibility of accurate transfer is improved. However, a problem occurs that the cost of the library system is increased.
Therefore, development of a library system capable of accurately transferring a cartridge and making it possible to reduce the manufacturing cost has been attempted so far. For example, the official gazette of Japanese Patent Publication No. 10-69689 discloses a system for accurately transferring a cartridge considering the error between the optical axis of a photosensor for measuring the position of an accessor and the operating axis of a hand assembly provided for the accessor for holing a cartridge in order to correct the error between driving signal of the accessor and the actual driving position.
An accessor is positioned by a photosensor when a laser beam is applied to a marking for positioning from a laser-beam source and the photosensor receives the reflected light of the laser beam. Simple and accurate positioning has been performed so far in accordance with the above configuration. However, the positioning by the photosensor still has a problem.
The problem is described below by referring to FIG.
9
.
FIG. 9
shows a marking
100
for positioning provided for the front of the above-described magnetic-tape drive. The above-described laser beam is scanned along a read range
114
. The marking
100
is located in the read range
114
and constituted of a black area
111
in black and white area
112
in white adjacent along the scanning direction L of the laser beam.
Thus, the boundary line
113
between the black area
111
and the white area
112
is identified when the reflected light of the laser beam changes from black to white through the above scanning. Because the position of the boundary line
113
is recognized, the position of the hand assembly is corrected in accordance with the position of the boundary line
113
and thereby, more precise positioning is performed.
However, the following problems occur in the above case.
First, because the marking
100
shown in
FIG. 9
is put on the surface of the frame of the magnetic-tape drive, the circumference of the marking
100
is enclosed by the color of the ground of the frame. When the color of the frame is a color between white and black (e.g. gray), the laser beam reflected before the marking
100
may be recognized as black or white. Therefore, it may be seen as the change from black to white before the marking
100
and a position different from the original boundary line
113
may be erroneously recognized as a boundary.
However, by narrowing the read range
114
of a laser beam (the width of the laser beam in its scanning direction is assumed as X) into the range of the sum of the scanning-directional width A of the black area
111
and the scanning-directional width B of the white area
112
(X<A+B), it is possible to eliminate the influence of the circumference of the marking. To narrow the read range
114
, however, it is necessary to improve the mechanical accuracy of an accessor mechanism and a problem occurs that the cost is resultantly increased.
The invention according to claim
1
comprises a magnetic-tape drive for at least reading data from a magnetic tape, an accessor mechanism for transferring a magnetic tape to and from the magnetic-tape drive, and a controller for controlling operations of the accessor mechanism.
Moreover, the accessor mechanism has a hand assembly for holding a magnetic tape and a predetermined-position detecting section provided for the hand assembly for detecting the predetermined position of the hand assembly to the magnetic-tape drive in accordance with the luminance of the reflected light due to scanning by a laser beam.
Furthermore, the magnetic-tape drive has a marking for positioning to be scanned by the laser beam. The marking is configured by two adjacent areas in black and white each other and these areas are arranged along the scanning direction of the laser beam.
Furthermore, the controller has a start position setting function for setting the scanning start position of the laser beam in a range closer to the marking than the sum of already-known widths of the two areas in their scanning directions before the marking and a positioning function for specifying the boundary between a black area and a white area in accordance with the change of luminances detected by the predetermined-position detecting section and already-known widths of the black area and white area in their scanning directions and positioning the hand assembly in accordance with the boundary position.
Operations will be described below. To position the hand assembly, scanning is performed by a laser beam from this side of the marking. Because the marking has black and white areas adjacent along the scanning direction, a state in which the luminance of the reflected light of the laser beam is low over the width of the black area and a state in which it is high over the width of the white area are continuously detected. Therefore, when the low luminance state is detected for the length equal to the already-known width of the black area and the high-luminance state following the low-luminance state is detected for the length equal to the already-known width of the white area, it is possible to specify the detection of the marking. Moreover, it is possible to specify that a position where luminances are greatly changed is present on the boundary line between the black area and the white area while the detection is performed.
On the other hand, because the area from a scanning start position up to this side of a marking which has been a problem so far is set to a value smaller than the width of the marking in its scanning direction, erroneous recognition of the marking in the this-side area cannot occur by specifying the marking by the above method.
In case of the invention according to claim
2
, a controller comprises a memory for storing the already-known width of a black area in its scanning direction and that of a white area in its scanning direction, an area extracting section for extracting a white area and a black area in accordance with a detected luminance, and an area specifying section for specifying a white area and a black area in accordance with the already-known widths of areas stored in the memory.
In case of the invention according to claim
3
, an accessor mechanism is characterized by being provided with a position detecting sensor for detecting the relative position relation between a hand assembly and a magnetic-tape drive and moreover, a controller has a roughly positioning section for positioning a hand assembly to a scanning start position in accordance with a relative positional relation for detecting a position detecting sensor.
In case of the invention according to claim
4
, a position detecting sensor uses a photosensor.
In case of the invention according to claim
5
, a black area is formed of a paint having a low light reflectance.
In case of the invention according to claim
6
, at least the range from a scanning start position up to a marking in the area around the marking is made gray.
In case of the invention according to claim
7
, areas of a marking are characterized by being arranged in order of a black area and a white area from a scanning start position toward the downstream side of a scanning direction.
In case of the invention according to claim
8
, areas of a marking are characterized by being arranged in order of a white area and a black area from a sca
NEC Corporation
Slavitt Mitchell
Sniezek Andrew L
Young & Thompson
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